Senior year first semester grades

First semester is about to end and my grades are not good in comparison to the first three years of high school. I am taking six AP’s and I have two B+'s and 2 A-'s in my classes. I’ve basically gotten straight A’s until now but I am scared that it will seem like I was slacking off this semester even though I am constantly studying or something school related. My grades dipped in the past two weeks because teachers have been piling everything up just to drop grades (yes, some are actually petty like that). Should I be worried?..